Jet propulsion engine with fuel injection means



Oct. 18, 1966 M. KEMENCZKY JET PROPULSION ENGINE WITH FUEL INJECTION MEANS Filed May 12, 1964 United States Patent 3,279,17Q JET PRUPULMON ENGHNE WliTl-ll FUEL HNJECTEUN MEANS;

Miklos Kemenezlry, Point Pleasant, Ni, assignor to Kcmenczky Establishment, Vaduz, Liechtenstein Filed May 12, 1964, Ser. No. 366,759 Claims. (Cl. 60-221) This invention relates to a jet propulsion engine for Watercraft, air-hydropulse pumping devices and similar structures. More particularly, the invention relates to an improved jet propulsion engine having fuel injection means incorporated therein.

The devices to which this invention relates are, in general, jet propulsion engines which are provided with a combustion chamber system wherein a fuel-air mixture is ignited in successive explosions to produce combustion gases which are thereafter fed into a thrust tube. The thrust tube is periodically filled with water which is ejected as a water column from the thrust tube due to the pressure of the combustion gases which are released by the explosions. A device of this kind is disclosed in my earlier filed application Serial No. 40,452, filed July 1, 1960, entitled Jet Propulsion Engine for Watercraft which issued as United States Patent No. 3,060,682 on October 30, 1962.

In such engines, the charge, consisting of a mixture of air and an easily combustible fuel, is drawn into a combustion chamber and ignited therein. A carburetor is employed for filling the combustion chamber with a fresh fuel mixture after each explosion. The fuel is drawn from the carburetor into the chamber by the action of the partial vacuum which arises in the chamber after each explosion. The etficiency of such a carburetor is greatly influenced by the rate of air which passes through the carburetor.

While conventional carburetors are satisfactory for the production of explosive mixtures at the air rates which occur in a conventional internal combustion engine, such carburetors are not as satisfactory for use in jet propulsion engines.

When used with jet propulsion engines, the conventional carburetors require widely different fuel-air ratios, depending upon the air rate through the carburetor. Because the patial vacuum created after each explosion determines the air rate passing through the carburetor, the air rate is a function of the power of each single explosion, provided the water column which is accelerated in the thrust tube is not completely ejected from the thrust tube. If a single explosion has suflicient power to eject the entire water column from the thrust tube, there is no longer sufficient vacuum to produce an air rate in the carburetor which is high enough to fill the combustion chamber system with the fuel-air mixture for the succeeding explosion. Thus, the succeeding explosion will have less power and will generate an even weaker vacuum. Ultimately, such a sequence will result in a breakdown or stoppage of the jet propulsion engine.

The above-mentioned difiiculties can be greatly diminished by the proper selection of combustion chamber system dimensions and thrust tube dimensions, as well as by proper adjustment of the air inlet to the carburetor. However, during the fast acceleration of such a jet propulsion engine, which occurs for example when the engine is employed in watercraft, and particularly during the starting period of such an engine, an increasing dynamic pressure is produced at the check valve which is located in the water inlet end of the thrust tube. This results in an undesirable pressure compensation with regard to the partial vacuum which arises in the thrust tube after each explosion. With increasing speed of the 3,279,179 Patented Get. 18, 1966 engine, relative to the surrounding water, this effect results in an increasing loss of the partial vacuum in the thrust tube and a diminishing of the air rate in the carburetor. The effect of this is a leaner air-fuel mixture so that the jet propulsion engine eventually reaches a point beyond which no further acceleration is possible. Carburetor adjustments have also been found to be frequently required when the engine is idling or being started, as well as when it is operating at high speeds.

The method in which the known carburetors function is also a factor in the difiiculties which can be encountered when such carburetors are employed with jet propulsion engines. The variation in time of the vacuum which occurs in jet propulsion engines and which affects the carburetor intake is different than for conventional engines. In a jet propulsion engine, the vacuum which occurs after each explosion normally has its highest value at the beginning of the vacuum cycle and decays asymptotically when the carburetor has been adjusted to produce a good firing mixture at an average air rate, such a carburetor produces leaner mixtures at lower air rates which are generally too lean to successfully operate the engine.

An additional disadvantage of the jet propulsion engine system employing a carburetor is the fact that in such engines the lean part of the explosive mixture is adjacent the spark plug and the rich part of the explosive mixture is found in the lower parts of the combustion chamber system. Because in such engines no compression or mixing of the gas components takes place prior to the ignition, it is possible to have weak or delayed explosions occuring. This is in contrast to a normal gasoline motor, in which the combustion mixture is compressed in the combustion chamber prior to its utilization, the compression period providing a good mixing of fuel and air. An additional deficiency of known jet propulsion engines is the limitation of the number of explosions which can occur during a time unit. This limitation results from the delay in the air intake. To obtain a sufficient dis persion of the liquid fuel in the carburetor, the air rate of the air being brought into the carburetor should be as high as possible and the air intake must be relatively small. Hence, the time necessary to completely fill the combustion chamber system limits the number of explosions per unit time, i.e. the explosion frequency.

The present invention eliminates or diminishes most of the disadvantages which are encountered when carburetors are employed in jet propulsion engines for watercraft. This result is accomplished, in accordance with the present invention, by providing a jet propulsion engine which has a precombustion chamber connected to a combustion chamber and which is provided with injection means connected to a fuel pump, said fuel pump being activated by varying pressures in the thrust tube.

It is an object of the present invention to provide an improved jet propulsion engine in which part of the energy being released by the moving column of water in the thrust tube is utilized to supply the combustion chamber system with fuel.

It is an additional object of the present invention to provide a smooth operating jet engine in which misfires are substantially eliminated.

It is a further object of the present invention to provide a jet propulsion engine for watercraft having a high explosion frequency.

These and other objects of the present invention will become more apparent from the following detailed description thereof which should be read with reference to the accompanying drawings, wherein:

FIG. 1 is a longitudinal setcional View of an embodiment of the jet propulsion engine of the present invention.

FIG. 2 is a plan view of the engine shown in FIG. 1.

FIG. 3 is a plan view of vortex ring 7 shown in FIG. 1.

Referring to FIGS. 1 and 2, there is shown jet engine 30 which is of a type more fully described in my United States patent application Serial No. 40,452 which issued as United States Patent 3,060,682. Jet engine 30 comprises block 31 and thrust tube 32. Precombustion chamher 2. is located in block 31 and, in this embodiment, is positioned above combustion chamber 3. Precombustion chamber 2 is connected to combustion chamber 3 in such a manner that the fuel-air mixture which is formed in precombustion chamber 2 will pass from precombustion chamber 2 through inlet valve 4 to combustion chamber 3. Precombustion chamber 2 is provided with nozzle 6 or other suitable injection means. Nozzle 6 is connected by means of pipe to fuel pump 1. A liquid fuel can be injected into precombustion chamber 2 under high pressure by means of nozzle 6.

Precombustion chamber 2 is provided with air intake ports 8 through which air can be drawn from the atmosphere. Intake ports 8 may be opened or closed by suitable means which may be manually or automatically operated in a conventional manner to provide the proper degree of air for combustion of the fuel which is injected through nozzle 6. In FIGS. 1 and 2, movable sleeve 17 can be moved vertically with respect to intake ports 8 to adjust the degree to which intake ports 8 are opened.

As can be seen from FIG. 3, vortex ring 7 is an annular ring positioned about midway along precombustion chamher 2. This ring, which is preferably employed, but which need not be employed, effects particularly thorough mixing of the fuel which is injected through nozzle 6 with the air which is drawn through air intake ports 3.

Combustion chamber 3 is shown divided by means of the flap-type valve 16 into two compartments, a first compartment 3a and a second compartment 3b. Combustion chamber 3 can be a single compartment, however, or can be divided by flap-type valves or similar valves into more than two compartments, if desired. The use of more than one compartment permits a higher pressure build up in the engine.

The second compartment 312 of combustion chamber 3 is connected through opening a to the chamber 9 of thrust tube 32. Opening 10a is provided with a valve means 10 which may be a flap-type valve or, as is shown, a hydrodynamic grid type valve of the type described and claimed in my co-pending application Serial No. 273,335, which was filed on April 16, 1963. Thrust tube 32 is provided with an annular inlet opening 33 which contains rotary check valve 11. Rotary check valve 11 may be constructed in a manner similar to that which is shown in my United States Patent 3,060,682 or the thrust tube may have valving means of the type shown in my co-pending United States application Serial No. 273,340, now Patent No. 3,157,992. The upper wall 9a of thrust tube 32 is provided with an opening 34 which contains within it disk 122. Disk 12 is attached to piston rod 14 and the movable unit consisting of piston rod 14 and disk 12 is free to move in a vertical direction through channel 14a and opening 3 1, respectively. Coil spring 13 is positioned in opening 34 with one end of coil spring 13 abutting the upper wall 34a of opening 34 and the other end of coil spring 13 abutting the upper wall 12a of disk 12, and urging disk 12 in a downward direction. The disk 12 c-losesopening 34 with respect to the chamber 9 of thrust tub-e 32, whenever the force of spring 13 is greater than the pressure which is produced in the chamber 9 within thrust tube 32. When the pressure within chamber 9 provides a force on disk 12 which is greater than the force of spring 13, disk 12 and piston rod 14 are moved upward against the pressure of spring 13. After the pressure of chamber 9 has fallen to atmospheric 0r sub-atmospheric pressure, disk 12 will, due to the action of spring 13, move to its idle position, as shown in FIG. 1.

During the normal operation of the jet propulsion engine 30, the piston rod 14 moves up and down in pump cylinder 19. Pump cylinder 19 is provided with check valve 1% of a known type which is located in the outlet of fuel line 18 which is connected to a fuel container (not shown). Through check valve 19!), which is also of conventional design, cylinder 19 is connected to pipe 5.

To start the jet propulsion engine 30, precombustion chamber 3 can be filled through tube 20 and opening 20a, or by other suitable means, with a combustible mixture of fuel and air. Opening 20a can be closed by a conventional valve (not shown). The combustible mixture is ignited by means of spark plug 15 or other suitable means. The resulting explosion creates a high pressure in combustion chamber 312 and thrust tube 32 which causes disk 12 and piston rod 14 to move upwards. The upward movement of piston rod 14 causes the liquid fuel from pump cylinder 19 to flow through check valve 1% and pipe 5 through nozzle 6, from which it is injected into precombustion chamber 2. Check valve 1% during this moment is closed to prevent a back flow of fuel through line 13. The amount of fuel, which may be gasoline or the like, supplied to nozzle 6 is adjusted in such a manner that a combustible fuel-air mixture is produced in precombustion chamber 2. During this period, which can be termed an injection period, spring check valve 4 is closed since the pressure in combustion chamber 3 is greater than the pressure in precombustion chamber 2. Vortex ring '7, during the intake of fuel and air into precombustion chamber 2, provides good mixing of air and fuel to produce an explosive mixture having a predetermined composition.

By selecting the proper dimensions of the pump cylinder 19 and of precombustion chamber 2, it is possible to prepare a fuel-air mixture in precombustion chamber 2 which is substantially constant in its amount and in its composition, regardless of the frequencies of explosion which take place in combustion chamber 3.

After each explosion in combustion chamber 3, the column of water which has been drawn into chamber 9 through inlet opening 33 and valve 11 is ejected from chamber 9 through outlet opening 35. A vacuum is then caused in combustion chamber 3, whereby spring check valve 4 is opened and the fuel-air mixture is drawn from precombustion chamber 2 through valve 4- to combustion chamber 3. The fuel-air mixture can then be ignited in combustion chamber 3 by means of spark plug 15 and the water which has entered chamber 9 of thrust tube 32 during the filling of combustion chamber 3 with a fuelair mixture is then ejected through outlet opening or port 35 by means of the combustion gases resulting from the explosion in combustion chamber 3. At the same time that the combustion gases are entering chamber 9 of the thrust tube, the pressure in chamber 9 is such that disk 12 and piston rod 14 are moved upwardly to pump additional fuel and air through fuel pump 1 and pipe 5 to nozzle 6 for the next explosion.

The injection process which is described, as well as the method which is employed to move the combustion mixture from precombustion chamber 2 to combustion chamher 3 are both carried out very rapidly and without any delays, since the air intake ports 8 and check valves 4 and 16 are provided with relatively large openings and flaps to permit the passage of relatively large volumes of fluids therethrough.

Intake ports 8 are adjusted to provide a volume of air which is suitable for the fast explosion frequency employed during normal operation of the engine. When the engine is started, and much lower explosion frequencies are employed, intake ports 8 may be partially closed by adjusting sleeve 17 to decrease the air intake, i.e. to throttle the air intake. The throttling of the air which is brought through intake ports 8 in this manner is important, since this permits the fuel-air mixture to be brought more slowly from the precombustion chamber 2 to the combustion chamber 3 and thus prevents the fuel-air mixture from entering through tube 32 before the fuel-air mixture has been burned. Such throttling also improves the suction of Water through the rotating check valve 11 into the thrust tube 32. This is a result which is desired during the starting process in order to provide sufiicient water in the thrust tube, since the dynamic pressure which would otherwise result from the motion of the motor in the water is absent during the starting period.

The present invention is particularly suitable when employed in the form of a jet propulsion engine for watercraft. For such use, the dynamic pressure which is developed by the motion of the engine through the water can be utilized to control the amount of air which is taken in through intake ports 8. This can be done by automatically adjusting the degree to which sleeve 17 closes intake ports 8 in accordance with the decrease of rotation of the rotating inlet check valve 11. The jet propulsion engine of the present invention may be employed for other purposes than the propulsion of watercraft, however. For example, it may be employed to pump liquids.

Obviously, the design and construction of the jet engine embodying the present invention can vary considerably from that shown in the figures. The combustion chamber, for example, can be arranged in a different orientation and the various valves can be modified or replaced by various substitutes, without departing from the spirit of the present invention. Thus, although my invention has been illustrated and described with reference to the preferred embodiments thereof, it is to be understood that it is in no Way limited to the details of said embodiments, but is capable of numerous modifications within the scope of the appended claims.

I claim:

1. A jet propulsion engine comprising a combustion chamber, ignition means therein for igniting a combustible fuel-air mixture in successive explosions, a thrust tube having a water inlet opening and an outlet opening and an opening provided with a valve which connects said thrust tube to said combustion chamber and which pe rmits the passage of combustion gases from said combustion chamber int-o said thrust tube in order to eject a water column which enters said inlet opening through said outlet opening, a precombustion chamber connected to said combustion chamber and provided with a fuel injection means, said injection means being connected to a fuel pump which is actuated by the pressure which results when combustion gases are introduced into said thrust tube from said combustion chamber.

2. The jet propulsion engine of claim 1, wherein said fuel pump comprises a piston designed for vertical motion and arranged to communicate at its lower end with an opening in the wall of said thrust tube, said piston being biased in a downward direction against said opening by biasing means, and said piston at its other end closing a pump cylinder and arranged to pump fuel from a fuel line to said injection means in response to a pressure in said thrust tube which is greater than the downward pressure of said biasing means.

3. A jet propulsion engine according to claim 1, having a vortex ring dividing said precombustion chamber into two communicating parts.

4. A jet propulsion engine according to claim 1, in which said precombustion chamber is connected to the said combustion chamber by an opening having a check valve which is normally closed and which is adapted to be opened for the passage of gas from said. precombustion chamber into said combustion chamber when a lower pressure exists in said combustion chamber than in said precombustion chamber.

5. A jet propulsion engine according to claim 1, in which said precombustion chamber is provided with an air intake orifice communicating with the surrounding air and having means for regulating the size of said orifice.

No references cited.

MARK NEWMAN, Primary Examiner.

C. R. CROYLE, Assistant Examiner. 

1. A JET PROPULSION ENGINE COMPRISING A COMBUSTION CHAMBER, IGNITION MEANS THEREIN FOR IGNITING A COMBUSTIBLE FUEL-AIR MIXTURE IN SUCCESSIVE EXPLOSIONS, A THRUST TUBE HAVING A WATER INLET OPENING AND AN OUTLET OPENING AND AN OPENING PROVIDED WITH A VALVE WHICH CONNECTS SAID THRUST TUBE TO SAID COMBUSTION GASES FROM SAID COMMITS THE PASSAGE OF COMBUSTION GASES FROM SAID COMBUSTION CHAMBER INTO SAID THRUST TUBE IN ORDER TO EJECT A WATER COLUMN WHICH ENTERS SAID INLET OPENING THROUGH SAID OUTLET OPENING, A PRECOMBUSTION CHAMBER CONNECTED TO SAID COMBUSTION CHAMBER AND PROVIDED WITH A FUEL INJECTION MEANS, SAID INJECTION MEANS BEING CONNECTED TO A FUEL PUMP WHICH IS ACTUATURE BY THE PRESSURE WHICH RESULTS WHEN COMBUSTION GASES ARE INTRODUCED INTO SAID THRUST TUBE FROM SAID COMBUSTION CHAMBER. 